In the field of communications it is known to provide systems in which a given device can obtain access to a network via access paths of differing access technology. This is shown schematically in FIG. 2. A communication system 10, e.g. a wireless communication device such as a mobile telephone is able to communicate with stations 11 and 12 that provide communication paths 101, 102 of a first access technology, e.g. a GSM (Global System for Mobile Communication) connection, a WCDMA (Wideband CDMA) connection, a WiMAX (Worldwide Interoperability for Microwave Access) connection, a WINNER (Wireless World Initiative New Radio) connection, a WLAN (Wireless Local Area Network) connection, etc. The communication system 10 can furthermore communicate with stations 13, 14 over communication paths 103, 104 that are of a different access technology than paths 101, 102. If the paths 101, 102 operate in accordance with one of the above-mentioned technologies, then the paths 103, 104 can be provided by any one of the other technologies. The communication system 10 accesses the network 15, e.g. a telephone network or a computer network, such as an intranet or the Internet via the paths 101-104.
If the stations 11-14 and the communication system 10 are arranged in such a way that the communication system 10 can from one location access the network 15 via both an access path 101, 102 or 103, 104, then this leads to the problem of managing the selection of one or more paths for conducting a communication session with the network 15.
The basic situation of having heterogeneous wireless technologies for communication in a given location has already been studied, e.g. in the context of so-called Ambient Networks (AN), see document ISD-2002-507134-AN/WB2/D02, MRA Architecture by Rolf Sigle et al, version 1.0, released Feb. 2, 2005. The inventors of the present application are also authors/editors of this document, the contents of which is herewith incorporated by reference.
In the context of Ambient Networks it has been proposed to use so-called Multi-Radio Resource Management (MRRM) for managing the different access technologies. An MRRM functionality coordinates the different radio access technologies by mapping service requests on available radio resources for both single- and multi-hop links. Different MRRM objectives can be used e.g. maximizing radio resource efficiency, service coverage or service quality, or enabling services otherwise impossible to deliver over a single radio access. Intelligent load distribution algorithms inside MRRM increase the overall effective network capacity. MRRM functions include advertising, discovery, selection, resource monitoring, and spectrum and congestion control. By monitoring the access paths and obtaining status information related to access paths of different access technology, an access controller can select an access path for a communication session in accordance with a selection procedure and in dependence of the status information.
Document EP 0 812 119 A2 discusses an improvement of the idle or standby mode in mobile stations of a cellular communication system. It is mentioned that the IS-136 and the GSM standard require an idle mobile station, i.e. a mobile station that is not in the process of conducting a communication session, to monitor control channels of neighbouring cells. EP 0 812 119 A2 proposes a different standby mode according to which when making measurements of a currently assigned control channel and other control channels, measurements of at least some of the other control channels can be terminated if it is detected that the mobile station has become stationary. The latter can be done by measuring the received signal strength of a monitored neighbouring channel and comparing the temporal change in signal strength with a predetermined threshold. If the change in received signal strength falls below this threshold it is determined that the mobile station is stationary.